RO unit selection with 45 TDS

[cpm6t]

I am going to convert my 220g freshwater tank to a reef tank. I have kept smaller saltwater tank before, using sea water ( I live within 200m of ocean) but bringing water from there is a pain.

This time I want to make my own water.

My tap water is 45 TDS. Should I just do with a RO system or do I need to go with RODI?

[Rover88]

You should always do RODI. The DI part is really not that much more expensive to add it on, and is the part that will get you to 0 TDS. Even 1 is 'too high' depending on how you look at it, as you don't know if that 1 TDS is copper.

On the plus side, your tapwater is 1/3 what mine is, so thats gonna allow your membrane and DI resin to last a fair bit longer.

The Membrane should reduce that by 95+% (so down to under 5 TDS) and then the DI will clean up the rest of it for you to zero.

[RobZilla04]

RODI as mentioned above. 45 TDS from tap is actually pretty good IMO. The filters should last you a while.

[cpm6t]

Thanks, that is what I gathered from reading previous posts, but just wanted to make sure since my tap water TDS is 45. :-)

[Rover88]

Originally Posted by cpm6t

Thanks, that is what I gathered from reading previous posts, but just wanted to make sure since my tap water TDS is 45. :-)

If you are going with a 230 gallon tank, a more important thing to consider is the GPD (Gallons per day) you can get out of your unit! If you ever want to do a water change, most people would say do 10-15% at a time, so for you thats around 25 gallons or more.

The rated GPD is in my limited experience in the best of conditions only; My unit claims 50 gallons per day, and in reality probably does 20 at best. I store about 25 gallons at a time for my auto-top off, and I use 10 for my water changes out of that when the time comes. (Pump it into a 10 gallon tank, mix salt, and then add it to the tank after removing 10 gallons manually).

If I could go back and redo, I'd spend double to triple what I spent for a better rated unit.

[mcgyvr]

Originally Posted by cpm6t

Thanks, that is what I gathered from reading previous posts, but just wanted to make sure since my tap water TDS is 45. :-)

A number is meaningless really.
Now if you can tell us exactly what they 45 tds is then you are better off..
Many people just use tap water and depending on what they 45 is you may be just fine with that..
But when it doubt go RO/DI and KNOW your water is good..

[hkgar]

The best RO membrane out there is this one:
http://spectrapure.com/NEW-99-percen...PD-RO-Membrane

[outy]

Originally Posted by cpm6t

my tap water TDS is 45. :-)

Mine is 29 and I always use ro/di

You can get away with cheap ebay membranes and you will still be 0 before DI

Your membranes and DI wil last a very long time, mine does.

I use 3 membranes recycling water and increasing production before my 2 Di stages with nuclear grade resin. No reason you could not do similar.

[outy]

Originally Posted by mcgyvr

A number is meaningless really.
.

No sir. there is a huge difference in how long membranes and DI resin last.

You can also use 3 membranes as a water saving and production increase you cannot do if your water is 250-400TDS

Its a very important number.

[mcgyvr]

Originally Posted by outy

No sir. there is a huge difference in how long membranes and DI resin last.

You can also use 3 membranes as a water saving and production increase you cannot do if your water is 250-400TDS

Its a very important number.

I'd hope you know what I meant by my comment..

Its basically useless to state "my TDS is 45 do I need RO or RO/DI?"
Without knowing what the 45 is the number is basically useless..

Now of course when choosing a membrane or a system then the TDS can be a good indicator as to how much filtration you may need but to just answer a question of RO or RO/DI the number doesn't do any good in answering that question..

[cpm6t]

Okay. I ordered a spectrapure 90 GPD 4 stage unit. It will take about a month to reach me since I'm on the other side of the world. Need to get a booster pump as well, which I can source locally.
Last time when I did this I first bought fish home, then ran to the ocean to get buckets of water to fill up my tank. Put the fish in and then did the plumbing. This time I'm going to take my time and do it in the proper order. :-)

[hkgar]

This is the booster pump I use and am very pleased. It is on Amazon, and others including Walmart, so may be available locally or by order? Good luck and happy reefing.

https://www.amazon.com/Aquatic-Life-.../dp/B00OMBPNHI